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so, is there any way (other than Multi Support Excitation) I can only apply ground acceleration to the support of a 3D structural model just like in practical condition.

Hello,

I have modelled a rectangular column element with fiber section (column height is 2m) and 'forceBeamColumn' element (shown below). At the time of dynamic analysis it shows error mentioned below but i have analysed same model with 'elasticBeamColumn' element it runs smoothly without any error.

## Sample Code (creating column elements)


# Define materials for nonlinear columns
# ------------------------------------------
# CONCRETE tag f'c ec0 f'cu ecu
# Core concrete (confined)
uniaxialMaterial Concrete01 1 -40.0e6 -0.004 -30.0e6 -0.02

# Cover concrete (unconfined)
uniaxialMaterial Concrete01 2 -40.0e6 -0.004 0.0 -0.006

# STEEL
# Reinforcing steel
set fy [expr 1.25*415e6]; # Yield stress
set Es 200e9; # Young's modulus
set dia 25e-3; # Diameter of the Reinforcing bar
set steelTagCol 3;
# tag fy E0 b
uniaxialMaterial Steel01 $steelTagCol $fy $Es $dia

# Define cross-section for nonlinear columns
# set some paramaters
set colWidth 0.5;
set colDepth 0.5;

set pi [expr 2.0*asin(1.0)];
set cover 0.05;
set d 0.025;
set As [expr ($pi/4)*(pow($d,2))]; ; # area of no. 1 bars

## C/S properties
set Mu 0.15; # Poisson's Ratio of concrete
set Ec 30e9; # Modulus of elasticity of concrete
set A_Col [expr $colWidth*$colDepth]; # Area of the Girder section
set IzC [expr ($colWidth*pow($colDepth,3))/12]; # MOI of the Girder section w.r.t. local Z axis
set IyC [expr ($colDepth*pow($colWidth,3))/12]; # MOI of the Girder section w.r.t. local Y axis
set JC [expr $colDepth*pow($colWidth,3)*((1/3)-(0.21*($colWidth/$colDepth)*(1-(pow($colWidth,4)/(pow($colDepth,4)*12)))))]; # Torsional MOI of rectangular section
set GC [expr ($Ec/(2*(1+$Mu)))]; # Shear Modulas of the section

set secIDCol 1; # section tag for section fibre

# some variables derived from the parameters
set y1 [expr $colDepth/2.0]
set z1 [expr $colWidth/2.0]

section Fiber $secIDCol -GJ [expr $GC*$JC] {

# Create the concrete core fibers
patch rect 1 10 10 [expr $cover-$y1] [expr $cover-$z1] [expr $y1-$cover] [expr $z1-$cover]

# Create the concrete cover fibers (top, bottom, left, right)
patch rect 2 10 5 [expr -$y1] [expr $z1-$cover] $y1 $z1
patch rect 2 10 5 [expr -$y1] [expr -$z1] $y1 [expr $cover-$z1]
patch rect 2 5 1 [expr -$y1] [expr $cover-$z1] [expr $cover-$y1] [expr $z1-$cover]
patch rect 2 5 1 [expr $y1-$cover] [expr $cover-$z1] $y1 [expr $z1-$cover]

# Create the reinforcing fibers (left, middle, right)
layer straight 3 3 $As [expr $y1-$cover] [expr $z1-$cover] [expr $y1-$cover] [expr $cover-$z1]
layer straight 3 2 $As 0.0 [expr $z1-$cover] 0.0 [expr $cover-$z1]
layer straight 3 3 $As [expr $cover-$y1] [expr $z1-$cover] [expr $cover-$y1] [expr $cover-$z1]

}

# set up geometric transformation of element
#set LinTransf 1;
set ColTransfTag 1;
geomTransf PDelta $ColTransfTag 0 0 1; # PDelta Transformation

# Setup Plastic hinge Properties

set Lpi 0.35; # Length of plastic Hinge at 'ith' end.
set Lpj 0.35; # Length of plastic hinge at 'jth' end.
set intgrPts 6;

# Define Column elements

set iColumn ""
set N0col [expr 10000]; # column element numbers
set level 0

for {set frame 1} {$frame <=[expr $NFrame]} {incr frame 1} {

for {set level 1} {$level <= [expr $ReqdFloors-1]} {incr level 1} {
for {set pier 1} {$pier <= [expr $NBayZ+1]} {incr pier 1} {
set elemID [expr $N0col +$level*$Dlevel + $frame*$Dframe+$pier]
set NodeI [expr $level*$Dlevel + $frame*$Dframe+$pier]
set NodeJ [expr ($level+1)*$Dlevel + $frame*$Dframe+$pier]

#element nonlinearBeamColumn $elemID $NodeI $NodeJ $intgrPts $secIDCol $ColTransfTag -intregation Legendre; # columns
element forceBeamColumn $elemID $NodeI $NodeJ $ColTransfTag HingeRadau $secIDCol $Lpi $secIDCol $Lpj $secIDCol;
#element forceBeamColumn $elemID $NodeI $NodeJ $intgrPts $secIDCol $ColTransfTag;
#element elasticBeamColumn $elemID $NodeI $NodeJ $A_Col $Ec $GC $JC $IyC $IzC $ColTransfTag;
}
}
}

##########....................################..................###############
The above 4 types of elements I have tried for column element.

## warnings and errors

WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20501(dW: << 0.0104173, dW0: 30936)
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20601(dW: << 0.0083161, dW0: 48321.2)
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20604(dW: << 0.000708733, dW0: 536217)
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 30603(dW: << 0.000124699, dW0: 44481.4)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain
WARNING AcceleratedNewton::solveCurrentStep() -the Integrator failed in update()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 2.915
OpenSees > analyze failed, returned: -3 error flag
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20603(dW: << -0.00284286, dW0: 1.84258e+06)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain
WARNING ModifiedNewton::solveCurrentStep() -the Integrator failed in update()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 2.915
OpenSees > analyze failed, returned: -3 error flag
Trying Newton with Initial Tangent ..
WARNING: CTestNormDispIncr::test() - failed to converge
after: 10000 iterations current Norm: 0.0153696 (max: 1e-06, Norm deltaR: 220884)
NewtnRaphson::solveCurrentStep() -the ConvergenceTest object failed in test()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 2.915
OpenSees > analyze failed, returned: -3 error flag
Trying Broyden ..
WARNING: CTestEnergyIncr::test() - failed to converge
after: 10 iterations
current EnergyIncr: 152.941 (max: 1e-06) Norm deltaX: 0.00521755, Norm deltaR: 706612
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20601(dW: << 207490, dW0: -323156)
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 20603(dW: << 3.22026e+06, dW0: -323007)
Domain::update - domain failed in update
Newmark::update() - failed to update the domain
WARNING ModifiedNewton::solveCurrentStep() -the Integrator failed in update()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 2.9175
OpenSees > analyze failed, returned: -3 error flag

####.......................#############......................########

and after few time steps analysis failed. please help with this issue why this is happening and how to rectify it??

Thank You

Hello,

I am trying to analyze a frame model with foundation at different level or height (i.e., foundations are on a slope) with 'Uniform Excitation Pattern'. Is it applying same ground motion to the foundation irrespective of their location or height (i.e., as same as frames on a plane ground or foundations are on the same height), or it works differently in case of foundation at a different height?

Thank You..

Thank you..

Hello,
I'm trying to record acceleration, velocity, and displacement data for nodes. what value will be recorded for acceleration, velocity and displacement if ground motion is applied by 'UniformExcitation' command ??

what I mean is, will the values be the relative values or absolute values ??

Thanks.

According to the OpenSees documentation 'Kinit' is the slope between Friction Coefficient (i.e., Mu) and displacement of the slider (i.e., dy/dz). Is it actual K (stiffness) of the slider or the different parameter of slider? what is actually 'Kinit' and how this parameter works? can anyone help it's bit confusing.

Thank You..

Hello,
I'm trying to model Friction damper with Flat Slider Bearing element. For Stick-Slip model of friction damper 'Kinit' should be ideally infinite. But for much higher value ( 1.0e15) it's showing numerical instability.

Can anyone help me with the 'Kinit' value for Flat Slider Bearing element when to be used as friciton damper?

Thank you.

I want to model Flexible diaphragm frame building. Can anyone help me about what type of materials, elements and joint connections are suitable for modeling of Flexible diaphragm.

Thank You.

I'm modeling a simple 3D frame using 2 different approaches for slab or diaphragm. In Rigid Diaphragm case time period is 0.07073167481663893 where as in Flexible Diaphragm case time period is 0.05693672810516015. My under standing is that for Rigid Diaphragm I should gate lower time period compare to Flexible Diaphragm. Can anyone kindly look into the code and point out the issue in modeling.

Copied below is the code.

Thank You.


wipe
wipe all

model BasicBuilder -ndm 3 -ndf 6;

set Rigid_Slab True;

# Create Nodes
# Command: node $nodeTag $X $Y $Z
node 1 0 0 0;
node 2 5 0 0;
node 3 0 0 5;
node 4 5 0 5;
node 5 0 4 0;
node 6 5 4 0;
node 7 0 4 5;
node 8 5 4 5;

# Fixing base nodes

fix 1 1 1 1 1 1 1;
fix 2 1 1 1 1 1 1;
fix 3 1 1 1 1 1 1;
fix 4 1 1 1 1 1 1;

# Define mass to nodes
set m 1000;
mass 5 $m $m $m $m $m $m;
mass 6 $m $m $m $m $m $m;
mass 7 $m $m $m $m $m $m;
mass 8 $m $m $m $m $m $m;

if {$Rigid_Slab == "True"} {
# Assigning Rigid Diaphragm

set PerpDirn 2;
node 7634 2.5 4 2.5;
fix 7634 0 1 0 1 0 1;
rigidDiaphragm $PerpDirn 7634 5 6 7 8;

} else {
# Define quadrilateral element for plate element

set matTag 99;
set E 13.0e9; # Modulus of elasticity of Mixed Southern Pine (According to AWC-NDS 2012, Table-4B)
set v 0.20;

# Define Material
nDMaterial ElasticIsotropic $matTag $E $v;

# Define section for slab
set secID 999;
set thick 0.150;
set elemID 888;

section PlateFiber $secID $matTag $thick;

element ShellMITC4 $elemID 5 6 8 7 $secID;
}
# Define materials for force columns

# CONCRETE tag f'c ec0 f'cu ecu
# Core concrete (confined)
uniaxialMaterial Concrete01 1 -44.0e6 -0.004 -36.0e6 -0.014

# Cover concrete (unconfined)
uniaxialMaterial Concrete01 2 -44.0e6 -0.004 1.0 -0.006

# STEEL
# Reinforcing steel
set fy 500e6; # Yield stress
set Es 200e9; # Young's modulus
set dia 25e-3; # Diameter of the Reinforcing bar
set steelTagCol 3;
# tag fy E0 b
uniaxialMaterial Steel01 $steelTagCol $fy $Es $dia

# Define cross-section for nonlinear columns
# set some paramaters
set Width 0.3
set Depth 0.3

set cover 0.04;
set As 3927e-6; # area of no. 8 bars

set secID 1; # section tag for section fibre

# some variables derived from the parameters
set y1 [expr $Depth/2.0]
set z1 [expr $Width/2.0]

section Fiber $secID {

# Create the concrete core fibers
patch rect 1 10 1 [expr $cover-$y1] [expr $cover-$z1] [expr $y1-$cover] [expr $z1-$cover]

# Create the concrete cover fibers (top, bottom, left, right)
patch rect 2 10 1 [expr -$y1] [expr $z1-$cover] $y1 $z1
patch rect 2 10 1 [expr -$y1] [expr -$z1] $y1 [expr $cover-$z1]
patch rect 2 2 1 [expr -$y1] [expr $cover-$z1] [expr $cover-$y1] [expr $z1-$cover]
patch rect 2 2 1 [expr $y1-$cover] [expr $cover-$z1] $y1 [expr $z1-$cover]

# Create the reinforcing fibers (left, middle, right)
layer straight 3 3 $As [expr $y1-$cover] [expr $z1-$cover] [expr $y1-$cover] [expr $cover-$z1]
layer straight 3 2 $As 0.0 [expr $z1-$cover] 0.0 [expr $cover-$z1]
layer straight 3 3 $As [expr $cover-$y1] [expr $z1-$cover] [expr $cover-$y1] [expr $cover-$z1]

}

# set up geometric transformation of element

set TransfTag 1;
geomTransf Linear $TransfTag 0 0 -1; # PDelta Transformation

set NumIntgrPts 5; # Number of Integration Points

# Define Column elements

element forceBeamColumn 1 1 5 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 2 2 6 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 3 3 7 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 4 4 8 $NumIntgrPts $secID $TransfTag;



# set up geometric transformation of beam element

set TransfTag 2;
geomTransf Linear $TransfTag 0 1 0; # PDelta Transformation

set NumIntgrPts 5; # Number of Integration Points

# Define beam elements

element forceBeamColumn 5 5 6 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 6 6 8 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 7 7 8 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 8 5 7 $NumIntgrPts $secID $TransfTag; # columns

# Eiven Analysis

set numModes 3
set lambda [eigen $numModes];

# calculate frequencies and periods of the structure ---------------------------------------------------
set omega {}
set f {}
set T {}
set pi 3.141593

foreach lam $lambda {
lappend omega [expr sqrt($lam)]
lappend f [expr sqrt($lam)/(2*$pi)]
lappend T [expr (2*$pi)/sqrt($lam)]
}

puts "periods are $T"

I have copied above written script and run it. But all the result is showing Zero. Can you check it again please and if you got any result other than zero please upload that result too. Thank you.

Yes nodal load is working properly but element load is not working. Actually elemental load is not working with any of nonlinear type of element.

wipe
wipe all

model BasicBuilder -ndm 3 -ndf 6;

# Create Nodes
# Command: node $nodeTag $X $Y $Z
node 1 0 0 0;
node 2 5 0 0;
node 3 0 0 5;
node 4 5 0 5;
node 5 0 4 0;
node 6 5 4 0;
node 7 0 4 5;
node 8 5 4 5;

# Fixing base nodes

fix 1 1 1 1 1 1 1;
fix 2 1 1 1 1 1 1;
fix 3 1 1 1 1 1 1;
fix 4 1 1 1 1 1 1;

# Define mass to nodes

mass 5 1000 1000 1000 0 0 0;
mass 6 1000 1000 1000 0 0 0;
mass 7 1000 1000 1000 0 0 0;
mass 8 1000 1000 1000 0 0 0;

# Define materials for force columns

# CONCRETE tag f'c ec0 f'cu ecu
# Core concrete (confined)
uniaxialMaterial Concrete01 1 -44.0e6 -0.004 -36.0 -0.014

# Cover concrete (unconfined)
uniaxialMaterial Concrete01 2 -44.0e6 -0.004 1.0 -0.006

# STEEL
# Reinforcing steel
set fy 500e6; # Yield stress
set Es 200e9; # Young's modulus
set dia 25e-3; # Diameter of the Reinforcing bar
set steelTagCol 3;
# tag fy E0 b
uniaxialMaterial Steel01 $steelTagCol $fy $Es $dia

# Define cross-section for nonlinear columns
# set some paramaters
set Width 0.5
set Depth 0.5

set cover 0.04;
set As 3927e-6; # area of no. 8 bars

set secID 1; # section tag for section fibre

# some variables derived from the parameters
set y1 [expr $Depth/2.0]
set z1 [expr $Width/2.0]

section Fiber $secID {

# Create the concrete core fibers
patch rect 1 10 1 [expr $cover-$y1] [expr $cover-$z1] [expr $y1-$cover] [expr $z1-$cover]

# Create the concrete cover fibers (top, bottom, left, right)
patch rect 2 10 1 [expr -$y1] [expr $z1-$cover] $y1 $z1
patch rect 2 10 1 [expr -$y1] [expr -$z1] $y1 [expr $cover-$z1]
patch rect 2 2 1 [expr -$y1] [expr $cover-$z1] [expr $cover-$y1] [expr $z1-$cover]
patch rect 2 2 1 [expr $y1-$cover] [expr $cover-$z1] $y1 [expr $z1-$cover]

# Create the reinforcing fibers (left, middle, right)
layer straight 3 3 $As [expr $y1-$cover] [expr $z1-$cover] [expr $y1-$cover] [expr $cover-$z1]
layer straight 3 2 $As 0.0 [expr $z1-$cover] 0.0 [expr $cover-$z1]
layer straight 3 3 $As [expr $cover-$y1] [expr $z1-$cover] [expr $cover-$y1] [expr $cover-$z1]

}

# set up geometric transformation of element

set TransfTag 1;
geomTransf Linear $TransfTag 0 0 -1; # PDelta Transformation

set NumIntgrPts 5; # Number of Integration Points

# Define Column elements

element forceBeamColumn 1 1 5 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 2 2 6 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 3 3 7 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 4 4 8 $NumIntgrPts $secID $TransfTag;



# set up geometric transformation of beam element

set TransfTag 2;
geomTransf Linear $TransfTag 0 1 0; # PDelta Transformation

set NumIntgrPts 5; # Number of Integration Points

# Define beam elements

element forceBeamColumn 5 5 6 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 6 6 8 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 7 7 8 $NumIntgrPts $secID $TransfTag;
element forceBeamColumn 8 5 7 $NumIntgrPts $secID $TransfTag; # columns

# Define recorders

recorder Element -file BeamForce.out -time -eleRange 5 8 force;
recorder Node -file NodeReaction.out -time -nodeRange 1 4 -dof 1 2 3 reaction;
recorder Element -file ColForce.out -time -ele 1 2 3 4 force;

# Define gravity load

pattern Plain 1 Linear {

eleLoad -ele 1 -type -beamUniform 0 0 -100e3;
eleLoad -ele 2 -type -beamUniform 0 0 -100e3;
eleLoad -ele 3 -type -beamUniform 0 0 -100e3;
eleLoad -ele 4 -type -beamUniform 0 0 -100e3;
eleLoad -ele 5 -type -beamUniform -100e3 0;
eleLoad -ele 6 -type -beamUniform -100e3 0;
eleLoad -ele 7 -type -beamUniform -100e3 0;
eleLoad -ele 8 -type -beamUniform -100e3 0;


}

# Gravity Analysis Parameters (load-controlled static analysis)

set Tol 1.0e-8; # convergence tolerance for test


constraints Plain; # how it handles boundary conditions
numberer RCM; # renumber dof's to minimize band-width (optimization), if you want to
system BandGeneral ; # how to store and solve the system of equations in the analysis (large model: try UmfPack)
test EnergyIncr $Tol 10 ; # determine if convergence has been achieved at the end of an iteration step
algorithm Newton; # use Newton's solution algorithm: updates tangent stiffness at every iteration
set NstepGravity 10; # apply gravity in 10 steps
set DGravity [expr 1.0/$NstepGravity]; # first load increment;
integrator LoadControl $DGravity; # determine the next time step for an analysis
analysis Static; # define type of analysis static or transient
analyze $NstepGravity; # apply gravity

loadConst -time 0.0 # maintain constant gravity loads and reset time to zero

puts "Model Built and Gravity Analysis done"

##########################################

Output for this script i.e. Node Displacement, Column Force etc.. is showing zero, whatever load is applied.

please anyone help me.